How to tell if guys just want to use you for aex

Katrina
Every time I'm around a guy I always get the classic excuse. You are attractive so of course I'm going to want to have sex with you. It just gets old. I just can't chill around s guy or should I say a man without them wanting sex. I know all guys want sex but it's usually the first 3 days we hang out. I just don't feel it's fair because I don't give off that vibes to guys or at least I don't think so. What are so things I can change so that won't happen??? By the way I already have a dedicated sex partner I want to be loyal to but he never available when I want to do something with him. So I guess my second question would be is what does this mean??? When we do get together the sexual chemistry is on point. But that's when I catch him and he not busy. What's should I do???